The present invention relates to a boot/ski binding assembly which can release in the event of falling both forward or backward and in response to twisting, consisting of a boot whose sole is fitted with a transverse bar and of a binding which has a longitudinal direction and a transverse direction and comprises means for retaining the boot by its bar.
U.S. Pat. No. 4,182,524, the content of which is incorporated by reference, discloses a boot/binding assembly in which the boot is fitted with two bars projecting on each side of the boot so as to form two pairs of studs used to secure the boot to a plate of the binding, this plate being itself mounted on a central block on which it is retained elastically in rotation by two rectangular frames bearing on two opposite flats of the central block. In this assembly, the means for releasing, on the one hand, when falling forward or backward and, on the other, in response to twisting, are separate from one another and are each controlled by their own elastic disengagement device. This binding is relatively complicated, and the studs form inappropriate projections on each side of the boot. Also, removing the boot from the binding requires compression of the release springs retaining the boot on the plate, and hence considerable effort.
Further, Patent Application EP 0 408 824, the content of which is incorporated by reference, discloses a boot/binding assembly in which the boot is fitted with two substantially vertical plates articulated about two axes parallel to the longitudinal direction of the boot, these plates interacting with retaining rollers that can be moved apart from one another when the boot is being fitted in the binding and in the event of falling forward or backward. These retaining rollers are mounted on a plate which is itself mounted on a central block about which the plate can pivot in the event of twisting forces, against the action of two springs. In this case as well, the means for releasing when falling forward or backward and in response to twisting are separate means controlled by their own spring an associated mechanism. In order to remove the boot intentionally, it is necessary to move apart the plates mounted on the boot, so that the means for actuating these plates are also located on the boot, which encumbers and complicates the boot.
U.S. Pat. No. 4,177,584, the content of which is incorporated by reference, presents a boot fitted with two transverse bars extending laterally beyond the sole on each side of the boot so as to form two pairs of studs intended to be retained by two pairs of arms of a ski binding. This binding is not described in this document, but it can be seen from the drawings that release in response to twisting is not possible.
Further, International Patent Application WO 97/22390, the content of which is incorporated by reference, discloses a snowboard binding consisting of a stirrup provided with two notches in which the transverse bar fitted to the boot engages by moving apart a pair of cams automatically wedging the bar in the notches. This binding does not, however, have any means of releasing the boot in the event of falling, and it is hence not a safety binding.
The safety bindings mentioned above are also susceptible to the build-up of snow which can easily prevent the boot from being fitted in the binding.
The object of the present invention is to provide a boot/ski binding assembly which is simpler than the assemblies known from the prior art, is less susceptible to the build-up of snow in the binding and requires less effort for removing the boot from the binding.
The boot/ski binding assembly according to the invention is one wherein the boot-retaining means located on the binding consist, on the one hand, of a transverse recess which has a notch-shaped profile and is formed between two pieces, at least one of which can be moved longitudinally against the action of at least one spring, and, on the other, of a self-locking cam articulated about an axis transverse to the binding on one of the pieces and urged to rotate by a spring tending to keep it engaged in the recess, the shape of the surface of the cam intended to come into contact with the bar being such that the bar, once engaged in the recess after having moved the cam away, tends to move the cam with it by friction when an upward force is exerted on the bar, so that the bar stays locked in the recess by wedging between the cam and the retaining piece which is not supporting the cam.
The boot is fitted with a single bar which does not extend laterally beyond the sole and works in its central region. In the event of falling, the effect of the force exerted on the bar is to push back the moving piece or pieces by bearing on the cam, both in the case when the bar experiences a force directed upward and when it experiences a twisting force. A single, relatively simple, system hence makes it possible to control release when falling forward or backward and release in response to twisting.
Given that the cam works as an element for taking up play and allows the bar to be wedged at any height over a certain range, the boot/binding assembly according to the invention is substantially unsusceptible to the build-up of snow in and on the binding. It is always possible to fit the boot in the binding quickly.
The boot can be fitted in the binding without effort, because this does not involve compressing the release spring or springs. When the boot is being fitted in the binding, the bar simply needs to move the cam away, optionally against the action of a weak return spring whose resistance is not in any event felt by the user.
Similarly, the boot is removed from the binding by acting on the cam, that is to say by pivoting it in the opposite direction to its locking direction. In this case as well, it is not necessary to compress the release spring.
According to a preferred embodiment of the invention, the two pieces of the retaining means can be moved longitudinally against the action of at least one common spring working in compression between two parts respectively secured to each of the two pieces.
The means for releasing the boot advantageously consist of a lever and a connecting element, such as a tie bent at its end, for rotating the cam in the opposite direction to its locking direction. This lever may be articulated to the front or rear of the binding for it to be actuated by hand or using a ski pole.